Room-Temperature Metal-Free Multicomponent Polymerizations of Elemental Selenium toward Stable Alicyclic Poly(oxaselenolane)s with High Refractive Index

Copper-catalyzed multicomponent polymerization of elemental selenium for regioselective synthesis of poly(5-diselenide-triazole)s

Herein, a unique multicomponent polymerization of elemental selenium, alkynes and azides was developed to prepare poly(5-diselenide-triazole)s with high regioselectivities and atom economy under mild conditions. Such selenium-containing triazoly polymers featured well-defined structures, high molecular weights (Mn up to 71 300 g mol-1) and yields (up to 90%), good solubility, high stability, and excellent redox-degradation properties.

Multicomponent Polymerization toward Poly(BODIPY-sulfonamide)s as Unique SO2 Generators for Sonodynamic and Gas Combination Therapy

In this work, a multicomponent polymerization (MCP) approach involving bipyrroles, sulfonyl azides, and diynes was developed to afford a library of poly(bipyrrole-sulfonylimide)s (PPSIs) in high yields and molecular weights, which were further modified to form unique sulfur dioxide (SO2) generators. Bipyrroles served as carbon-based nucleophiles to undergo Cu-catalyzed C-C coupling during the MCP. Upon post-MCP modification by transforming the bipyrrole unit to boron dipyrromethene (BODIPY) and the sulfonylimide moiety to sulfonamide, poly(BODIPY-sulfonamide)s (PBSAs) were obtained as potent anticancer therapeutic agents. This study disclosed the decomposition and SO2-releasing ability of PBSAs under ultrasound (US) irradiation. Furthermore, one of these polymers having a reactive oxygen species-cleavable thioketal linker was modified with triethylene glycol chains to give PBSA-EG, which was further studied for in vitro and in vivo US-induced anti-cancer therapy. Upon tail veil administration of PBSA-EG nanoparticles into tumor-bearing mice followed by US irradiation, remarkable tumor suppression was observed. This study demonstrates that the innovative and efficient MCP method can construct polymers bearing the BODIPY-sulfonamide moieties, which show a great potential as safe and potent materials for combined gas and sonodynamic therapy against cancer.

Water-Involved Carbon-Nitrogen Triple-Bond Monomer Based Polymerization toward Processable Functional Polyamides under Ambient Conditions

Polyamide plays a pivotal role in engineering thermoplastics. Constrained by the harsh conditions and arduous procedures for its industrial synthesis, developing facile synthesis of polyamides is still challengeable and holds profound significance. Herein, we successfully utilized water as one of the monomers to synthesize functional polyamides under ambient conditions. A powerful multicomponent polymerization of water, isocyanides, and chlorooximes was established in phosphate-buffered saline. Soluble and thermally stable polyamides with high weight-average molecular weights (up to 53 900) were obtained in excellent yields (up to 95 %). The polymerization exhibits unique polymerization-induced emission characteristics, successfully converting non-emissive monomers into unconventional emissive polymers. Notably, the resultant polyamides could undergo effective post-modification via the hydroxyl-yne click reaction. By incorporating various functional groups into the polyamide, its emission color could be fine-tuned from blue to green and to red. Remarkably, the refractive index (n) of the polyamide at 589 nm could be increased from 1.6173 to 1.7227 and the Δn could be unprecedentedly as high as 0.1054 for non-heavy atom-containing polymers after post-modification, and its micron-thick films exhibited excellent transparency in the visible region. Thus, this work not only establishes a powerful polymerization toward novel polyamides but also opens up an avenue for their versatile functionalization.

Efficient Conversion of Inert Nitriles to Multifunctional Poly(5-amino-1,2,3-triazole)s via Regioselective Click Polymerization with Azide Monomers under Ambient Conditions

Nitrile compounds are abundant, stable, cheap, and readily available natural and chemical industrial sources. However, the efficient conversion of nitrile monomers to functional polymers is mostly limited due to their inert reactivity, and developing efficient polymerizations based on nitrile monomers under very mild conditions is still a big challenge. In this work, a facile and powerful base-catalyzed acetonitrile-azide click polymerization was successfully established under ambient conditions. This polymerization also enjoys the merits of short reaction time (15 min), 100% atom economy, transition-metal-free catalyst system, and regioselectivity. A series of poly(5-amino-1,2,3-triazole)s (PATAs) with high weight-average molecular weights (Mw, up to 204,000) were produced in excellent yields (up to 99%). The PATAs containing tetraphenylethene (TPE) moieties exhibit unique aggregation-induced emission (AIE) characteristics, which could be used to sensitively detect Fe(III) ions with a low limit of detection (1.205 × 10-7 M) and to specifically image lysosomes of living cells. Notably, PATAs could be facilely post-modified due to their containing primary amino groups in the polymer chains even through a one-pot tandem reaction. Thus, this work not only establishes a new powerful click polymerization to convert stable nitriles but also generates a series of PATAs with versatile properties for diverse applications.

One-pot multicomponent polymerization towards heterocyclic polymers: a mini review

Multicomponent polymerization (MCP) is an innovative field related to polymer-based chemistry that offers numerous advantages derived from multicomponent reactions (MCRs). One of the key advantages of MCP is its ability to achieve high efficiency. Additionally, MCP offers other advantages, including operational simplicity, mild reaction conditions, and atom economy. MCP is a versatile technique that is used for synthesizing a wide range of analogs from several classes of heterocyclic compounds. The ring structures of heterocyclic polymers give them different mechanical, photophysical, and electrical properties to other types of polymers. Because of their unique properties, heterocyclic polymers have been widely utilized in various significant applications. MCRs are a type of chemical reaction that can be used to synthesize a wide variety of compounds in a single pot, which allows researchers to quickly assemble libraries of compounds. The development of MCPs from MCRs has made it easier to access a library of polymers with tunable structures. However, MCPs related to alkynes or acetylene triple bonds have more potential. In this review study, we provide an overview of the synthesis of heteroatom-functional polymers and alkyne-based development or other reactions such as Cu-catalyzed, catalyst-free, MCCP, MCTPs, green monomers, A3 coupling reactions, Passerini reactions, and sequence- and controlled-multicomponent polymerization. The up-to-date progress provides a convenient and efficient kind of approach related to heteroatoms and MCP synthesis, and perspectives in terms of future directions are also discussed in the study.

High Refractive Index Polymer Thin Films by Charge-Transfer Complexation

High refractive index polymers are essential in next-generation flexible optical and optoelectronic devices. This paper describes a simple synthetic method to prepare polymeric optical coatings possessing high refractive indexes. Poly(4-vinylpyridine) (P4VP) thin films prepared using initiated chemical vapor deposition are exposed to highly polarizable halogen molecules to form stable charge-transfer complexes: P4VP-IX (X = I, Br, and Cl). Fourier transform infrared spectroscopy was used to confirm the formation of charge-transfer complexes. Characterized by spectroscopic ellipsometry, the maximum refractive index of 2.08 at 587.6 nm is obtained for P4VP-I₂. For P4VP-IBr and P4VP-ICl, the maximum refractive indexes are 1.849 and 1.774, respectively. By controlling the concentration of charge-transfer complexes, either through the halogen incorporation step or polymer composition through copolymerization with ethylene glycol dimethacrylate, the refractive indexes of the polymer thin films can be precisely controlled. The feasibility of P4VP-IX materials as optical coatings is also explored. The refractive index and thickness uniformity of a P4VP-I₂ film over a 10 mm diameter circular area were characterized, showing standard deviations of 0.0769 and 1.91%, respectively.

Transcending the Trade-off in Refractive Index and Abbe Number for Highly Refractive Polymers: Synergistic Effect of Polarizable Skeletons and Robust Hydrogen Bonds

High-refractive-index polymers (HRIPs) are attractive materials for the development of optical devices with high performances. However, because practical components and structures for HRIPs are limited from the viewpoint of synthetic techniques, it has proved difficult using traditional strategies to enhance the refractive index (RI) of HRIPs to more than a certain degree (over 1.8) while maintaining their visible transparency. Here, we found that poly(phenylene sulfide) (PPS) derivatives featuring both methylthio and hydroxy groups can simultaneously exhibit balanced properties of an ultrahigh RI of n _D = 1.85 and Abbe number of ν_D = 20 owing to the synergistic effect of high molar refraction and dense intermolecular hydrogen bonds (H-bonds). This brand new strategy is anticipated to contribute to the development of HRIPs displaying ultrahigh RI with adequate Abbe numbers beyond the empirical n _D-ν_D threshold, which has not been achieved to date.

One-Pot Multicomponent Polymerization, Metal-, and Non-Metal-Catalyzed Synthesis of Organoselenium Compounds

The one-pot multicomponent synthetic strategy of organoselenium compounds represents an alternative and robust protocol to the conventional multistep methods. During the last decade, a potential advance has been made in this domain. This review discusses the latest advances in the polymerization, metal, and metal-free one-pot multicomponent synthesis of organoselenium compounds.

Diselenide–yne chemistry for selenium-containing linear polymer modification

Selenium-containing brush polymers with diverse functional segments were easily prepared through diselenide–yne chemistry.

Synthesis of Colorless and High-Refractive-Index Sulfoxide-Containing Polymers via the Oxidation of Poly(phenylene sulfide) Derivatives

Highly refractive, thermostable, and transparent poly(phenylene sulfide) (PPS) derivatives partially including S=O bonds were reported. The polymers were prepared via m-chloroperbenzoic acid (mCPBA) oxidation of the corresponding PPS derivatives, affording...

Clusterization-Triggered Color-Tunable Room-Temperature Phosphorescence from 1,4-Dihydropyridine-Based Polymers

A series of poly(1,4-dihydropyridine)s (PDHPs) were successfully synthesized via one-pot metal-free multicomponent polymerization of diacetylenic esters, benzaldehyde, and aniline derivatives. These PDHPs without traditional luminescent units were endowed with tunable triplet energy levels by through-space conjugation from the formation of different cluster sizes. The large and compact clusters can effectively extend the phosphorescence wavelength. The triplet excitons can be stabilized by using benzophenone as a rigid matrix to achieve room-temperature phosphorescence. The nonconjugated polymeric clusters can show a phosphorescence emission up to 645 nm. A combination of static and dynamic laser light scattering was conducted for insight into the structural information on formed clusters in the host matrix melt. Moreover, both the fluorescence and phosphorescence emission can be easily tuned by the variation of the excitation wavelength, the concentration, and the molecular weight of the guest polymers. This work provides a unique insight for designing polymeric host-guest systems and a new strategy for the development of long wavelength phosphorescence materials.